Improvement in furnaces for burning pulverized fuel



1 11516 PATENTE FEB' 71871 that@ situa anni @time THOMAS RUSSELL GRAMP'ION, OF WESTMINSTER, LONDONGREAI BRITAIN.

Letters Parent No. 111,616,11atearebmry 7,1871.

IMPROVEMENT IN 'FuRNAcr-:s'FoR suRNlNcvPuLvsRizEn Fusi...

The Schedule referred to inv thesev Letters Patent and making part of the ame.

skilled in the art to which my invention fumertains` to make and use the same.

This invention consists in constructing a furnace in which a plain combustion-chamber also constitutes the working-chamber, and in which .the mixture of air. and powdered fuel is lintroduced near the neck or exit-flue thereof, in a manner to cause them to move toward the closed end of the chamber in a circuitous course therein, to prevent their separating from one another; and also to cause the several currents diverging from the incoming stream or'streams of air `and coal, to mingle and unite with one another, so as to keep the mixture good. Y

' M y invention also consists in the arrangement of the issues of the conduct-ing pipes, so that the streams of fuel-charged air will pass near the upper surface of the furnace and be mixed by causing them to impinge upon and against each other on their route tothe closed end and return mixed between the incoming currents and the material under treatment; the direction of the issues of these pipes being such as to -cause the incoming current-s to traverse through the center of 'the' chamber, or nearly so, because, if the stream of fuel-charged air were directed on one side of the chainber by a single jet, particularly if unmixedon entering the chamber, and traversing its outline, the air .and fuel would not keep together suliciently ou their route topi-educa the best results, and carbon dust would be in most casesdeposited in the chamber and on the material .under treatment, and cause consider- 'able waste' of f uel andiuconveniencc.

. In a patent hearing' even date herewith I have de scribed and represented the mechanism for and mode of feeding, dividing, conducting, and injecting fuelcharged air in proper proportions for keeping up a good mixture in the furnace; a description, therefore,

oftbesc things is deemed unnecessary here.

lhc accompanying drawing represents a vertical" and horizontal section of a furnace, A having a single plain chamber, B, extending fronthe iront end thereof to the neck C of the chimney D, so as to have the use cf the entire furnace as a workingchamber, thus having but one chamber within which to consume the fuel and do the work. This chamber is closed, and is without vgrate-bars or draught openings whatever.v

lhe rireibridgenlfl is formed across the neck of the furnace so as to raise the exit-opening above the bottom of the furnace, and th'us form a chamber or basin for molten metal, from which it may be tapped through f a door in the side or end of the furnace.

` From thetop of this bridge the neck of the chimney descends so as to bring the end of the neck which which forms a junction with the chimney-line below the bottom ofthe working-chamber.

, The conducting-pipes 11 for the fuel-charged air are arranged tochter the back end of the 'chamber at or near -the top. thereof, so as to inject the currents of fuel-charged air into the furnace in a direction ,away from the chimney or outlet.

lhesc pipes are also arranged to enter the furnace so that the. currents therefrom wiliimpinge upon each other obliquely at or near the middle'of the width ot' the chamber and nearly above the fire-bridge.

By this means thc currents are caused to take n central direction through the length of the chamber,- and near the uppeusuriace thereof, so that iu passing toward the closed front end the products 'of combustion turn downward immediately over and upon the material placed on the bottom, spreading out to either side as the ilarne descends, whereby the larger particles in the stream ofair and coal which are ,not consumed before reaching; this point arelconsumed on .their return passage toward the neck ofthe furnace.

In order also to effect perfect-combustion of a stream or streams of air and fuel blown into a furnace, or into a combustion chamber, the fuel-charged air must Yhe injected at such a velocity that .the currents shall not .strike 'or but slightly strike against the opposite side or end of t-hc furnace to that at whichthey are injected.

In the example shown it will be seen that the momentum of the incoming streams is absorbed by the countcracting effect of their impingement upon each other at an angle, and the equilibrium of the charge l of fuel and air is thereby more thoroughly diffused and maintained, and all tendency to undue separation of nir and fuel into separate streams or to the deposit of iueficieutly-consumed fuel 1s avoided.

The conducting-pipes enter the chamber obliquely from the opposite sides of the furnace, and there may be two. or more such pipes entering the chamber' at the saine or dilercnt angles, so as to ,direct the streams parallel, or nearly so, to the top of the furnace; or a series of issues placed parallel to each other and lengthwise of the chamber may be used to project the currents in the same manner and cause the products of combustion to return iu. the'chamber between the work and the incoming streams.'v

The velocity of the incoming streams should not be great enough to cause them to impinge against 'chel end of tbe furnace with any considerable force, because the greater the force of irnpingement,t1|e

more excessive the wear of the furnace, which should l ,It must be understood,however, when furnaces are working with a partial vacuum that there-must be sucient force in the injected'mixtnre of air and fuel -to enter the chamber freely when the vacuum of thc furnace is reduced by the door being opened, or otherwise, so as to prevent the fuelaud air being' retained in the conducting pipes, particularly where the pipes are of some length and contain bends; also to prevent the fuel-charged air blowing back in the event ""f the fuel being fed into the pipes close to the fur- The working-chamber of -the furnace is made of reresisting material, and forms .at the same time the combustion chamber, thus combiningr the two in one, and by this-arrangement I am enabled to obtain.

a much smaller lfurnace than heretofore, combining the capacity of the two separate chambers heretofore builtin-thc same furnace. f

Among theadvantges of this form andarrangement of fumaeennd injecting pipes` is the utili-sation of the waste heat of the escaping products of combustion by causing thenrto pass iu contact with the incoming streams of fuel and air.

The furnace is charged and the fire is kindled through a door, G, in the side ofthe furnace.

The issues ofthe pipes may be merged into a nar row thin,l jet, in .which case care must -be taken that the change from the round to the narrow form mustbe gradual, in order to insure the mixture being maiutained at the end of the furnace, but I prefer separate round jets.

l The air and fuel issuing from each jet are not, as a rule,` properly mixed, particularly where curves or' bends are made in the introducing-pipes near the furnace, v

Inns'uch cases it will be found that the particles ot' fuel carried in suspension in the streams of air, gatner ou the outside of the bend in the pipes, by reason of ltheir greater specific gravity; andin order to insure that the surchargcd and undercharged `portions of such streams shall impinge upon and against' each other, I place the bends ofthe pipes 'in opposite directions, and in this -way produce a compensating mingling of the streams, and maintain the equilibrium patent granted to me.

I do not claim injecting or ioatinar pnlverizcd fuei into the body of a furnace, as ldescribed in the patents of \Vhelpley and Storex', :dated March 13, 1866, reissue No. 3,857, and May 31, 1870, No. 103,695.

In my improvement the pulver-ized fuel mixed with air, enters at the rear of the furnace, and is tur-ned back, so as 'to leave in a directionl opposite to that at which it entered, so that the incoming streams of air and fuel pass over, and are heated by the reflected or out-going current within the combustion chamber; as shown.

Having described my invention,

l. The fuel-charged air, for the combustion, injected into the furnace at the rear end thereof, and near the products of combustion escape, as described.I

2.- 'Ihe fuel-charged air, for thelcombustio. injected into the furnace at or near the top thereofv so es to be caused to pass toward the front end of the chamber, turn down and return between the if com ng streams and the metal'uuder treatment, as described 3 A furnace, constructed and adapted to receive the fuel-charged air at its rear end, and in wh'icn the work is done in one and'fthe same chamber within which the combustion takes place, as described.

4.. ,'lhe arrangement of au incoming 'and returning current of air and fuel within" the combustion cham- 'sho'win n T. R. CRAMPTON.

Westminster. Imm

of the fuel-charge, as more fully described in another neck, in the opposite direction from that in which the .l

ber, ,soV that thelformer is heated by the latter, as 

